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Intact Plasma Membrane (intact + plasma_membrane)
Selected AbstractsEffect of Ram Age on Structural and Functional Competence of Frozen,Thawed Spermatozoa in Dairy SheepREPRODUCTION IN DOMESTIC ANIMALS, Issue 4 2010AG Lymberopoulos Contents The objectives of this study were to investigate the influence of ram age on structural and functional competence of frozen,thawed spermatozoa and to test the hypothesis that increasing number of sperm bound to the zona pellucida in vitro was associated with decreasing in vivo fertility of frozen semen. Rams were allocated into two groups. Each group consisted of five rams aged either 1,2 years (young) or 4,5 years (mature). Three successive ejaculates were collected from each ram using an artificial vagina. Only ejaculates of , 2.5 × 109 sperm/ml and 80% sperm progressive motility were pooled per ram, diluted with Bioxcell® medium and frozen in 0.25 ml straws. The end points of post-thawing semen evaluation were computer-assisted cell motility analysis, sperm capacitation (chlortetracycline assay), simultaneous assessment of plasma membrane integrity, mitochondrial membrane potential and condensation status of nucleus, per-cell analysis of lipid peroxidation using C11-BODIPY581/591, sperm-hemizona binding (HZB) ability and sperm fertility after laparoscopic insemination of ewes (n = 114) in the progestagen-synchronized oestrus. The results showed that mature rams had significantly lower values of sperm hyperactivated motility and peroxidized sperm, higher percentages of live non-capacitated sperm and sperm cells with intact plasma membrane, functional mitochondria and condensed chromatin, as well as, greater lambing rate and ewe prolificacy. Sperm HZB binding ability was higher (p < 0.05) for young than for mature rams. Significant correlations were found between number of spermatozoa bound to the zona pellucida and semen fertility (r = ,0.63 to ,0.71). In conclusion, mature rams have better semen quality and in vivo fertility than young rams. Cryocapacitation can be involved in decreasing ram semen fertility as evidenced by the high number of spermatozoa bound to the zona pellucida in vitro. [source] Evaluation of Fertilizing Potential of Frozen-thawed dog Spermatozoa Diluted in ACP-106® using an In Vitro Sperm,Oocyte Interaction AssayREPRODUCTION IN DOMESTIC ANIMALS, Issue 1 2007RCS Cardoso Contents The aim of present study was to evaluate frozen canine semen with ACP-106® (Powder Coconut Water) using an in vitro sperm,oocyte interaction assay (SOIA). Ten ejaculates from five stud dogs were diluted in ACP-106® containing 20% egg yolk, submitted to cooling in a thermal box for 40 min and in a refrigerator for 30 min. After this period, a second dilution was performed using ACP-106® containing 20% egg yolk and 12% glycerol. Samples were thawed at 38°C for 1 min. Post-thaw motility was evaluated by light microscopy and by using a computer aided semen analysis (CASA). Plasma membrane integrity and sperm morphology/acrosomal status were evaluated by fluorescent probes (C-FDA/PI) and Bengal Rose respectively. Moreover, frozen-thawed semen was analysed by a SOIA. Subjective post-thaw motility was 52.0 ± 14.8% and it was significant higher than the total motility estimated by CASA (23.0 ± 14.8%) because this system considered the egg yolk debris as immotile spermatozoa. Although normal sperm rate and acrosomal integrity evaluated by Bengal Rose stain was 89.6 ± 3.1% and 94.3 ± 3.1%, respectively, post-thaw percentage of intact plasma membrane was only 35.1 ± 14.3%. Regarding SOIA, the percentage of interacted oocytes (bound, penetrated and bound and/or penetrated) was 75.3%. Using regression analysis, it was found significant relations between some CASA patterns and data for SOIA. In conclusion, the freezing-thawing procedure using ACP-106® was efficient for maintain the in vitro fertility potential of dog spermatozoa. [source] Neural stem cells improve neuronal survival in cultured postmortem brain tissue from aged and Alzheimer patientsJOURNAL OF CELLULAR AND MOLECULAR MEDICINE, Issue 5a 2008L. Wu Abstract Neurodegenerative diseases are progressive and incurable and are becoming ever more prevalent. To study whether neural stem cell can reactivate or rescue functions of impaired neurons in the human aging and neurodegenerating brain, we co-cultured postmortem slices from Alzheimer patients and control participants with rat embryonic day 14 (E14) neural stem cells. Viability staining based on the exclusion of ethidium bromide by intact plasma membranes showed that there were strikingly more viable cells and fewer dead cells in slices co-cultured with neural stem cells than in untreated slices. The presence of Alzheimer pathology in the brain slices did not influence this effect, although the slices from Alzheimer patients, in general, contained fewer viable cells. Co-culturing with rat E14 fibroblasts did not improve the viability of neurons in the human brain slices. Since the human slices and neural stem cells were separated by a membrane during co-culturing our data show for the first time that neural stem cells release diffusible factors that may improve the survival of aged and degenerating neurons in human brains. [source] Astrocytes are More Resistant to Focal Cerebral Ischemia Than Neurons and Die by a Delayed NecrosisBRAIN PATHOLOGY, Issue 4 2009Günfer Gürer Abstract Several recent reports proposed that astrocyte death might precede neuronal demise after focal ischemia, contrary to the conventional view that astrocytes are more resistant to injury than neurons. Interestingly, there are findings supporting each of these opposing views. To clarify these controversies, we assessed astrocyte viability after 2-h middle cerebral artery occlusion in mice. In contrast to neighboring neurons, astrocytes were alive and contained glycogen across the ischemic area 6 h after reperfusion, and at the expanding outer border of the infarct at later time points. These glycogen-positive astrocytes had intact plasma membranes. Astrocytes lost plasmalemma integrity much later than neurons: 19 ± 22 (mean ± standard deviation), 58 ± 14 and 69 ± 3% of astrocytes in the perifocal region became permeable to propidium iodide (PI) at 6, 24, 72 h after ischemia, respectively, in contrast to 81 ± 2, 96 ± 3, 97 ± 2% of neurons. Although more astrocytes in the cortical and subcortical core regions were PI-positive, their numbers were considerably less than those of neurons. Lysosomal rupture (monitored by deoxyribonuclease II immunoreactivity) followed a similar time course. Cytochrome-c immunohistochemistry showed that astrocytes maintained mitochondrial integrity longer than neurons. EM confirmed that astrocyte ultrastructure including mitochondria and lysosomes disintegrated much later than that of neurons. We also found that astrocytes died by a delayed necrosis without significantly activating apoptotic mechanisms although they rapidly swelled at the onset of ischemia. [source] | ||||||||||